Human brain tumors and central nervous system tissues are being grown in tissue culture for the purposes of carrying out microcytotoxicity tests in order to evaluate the presence or absence of cell-mediated immune responses in patients with brain tumors. Various chemotherapy and immunotherapy protocols are being carried out in animal model system (avian sarcoma virus induced brain tumors in rats) in an effort to evaluate various adjunctive treatment protocols for possible use in treating malignant brain tumors. Efforts will likely be made to try to determine the presence or absence of blocking factor in the sera of patients with brain tumors.